
T400 Controller Facilities Manual
667/EB/20200/000 Page 25-19 Issue 9
25.4.2 Operation On Second Red Lamp Fail
The operation of the controller when a second red lamp fails (RLF2 indication) can be
configured for each RLM group to one of the following - see config items (C3) and
(C5):-
a) For Pedestrian RLM
Inhibit selected phases - normally pedestrians - from appearing and insert
permanent demands for these phases (so that wait indicators are illuminated on
inhibited pedestrian phases).
If the inhibited phases are already at green, special conditioning can be used to
terminate the phases on expiry of the minimum greens.
If the failure occurs while the controller is moving to a stage where an inhibited
phase would appear, but the phase has not yet started to change from red, then
the inhibited phase will continue to show red for the duration of the stage. On
subsequent cycles, a stage which only contains inhibited phases will not be run.
NOTE: When configuring inhibits, the inhibited phases should be configured as
optional within the stage.
or b) For Part-Time Signals
Set selected phases to blackout, irrespective of the current phase display (red,
min green, amber etc.). Care must be taken when configuring to ensure that all
phases on a stream are blacked out.
NOTE: Setting phases to blackout does not disable green correspondence
checking, i.e. the greens still checked that they are off.
The second red lamp failure is actioned within 500mS of the failure occurring.
A feeder failure or a failure of the RLM unit, are actioned as for a second red lamp
failure.
Where the RLF2 signal is used to blackout phases, these phases will not be allowed on
again until the RLF2 signal is removed and the controller has powered off and on. This
ensures that the lamps follow the required start-up sequence.
When the faulty lamps have been replaced on a part-time controller, the operator
enters KRD=1 to remove the RLF2 signal, enters RFL=1 to clear the fault from the
controller and then powers the controller off and on. On powering up, the lamps will
come on as normal. If the faulty lamps have not been replaced then the signals are
switched off again as soon as the failed aspect appears, since the integral RLM unit will
detect the faulty load and re-assert RLF2.
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